05.30.00

Here's what I did to get I and R band magnitudes of ser_yprime.

1.  Get the Hawaii I band image.

2.  Pick out some stars to get the seeing, sky, variance in sky,
    etc.  Do this with daoedit in the noao.digiphot.daophot package.  You
    want unsaturated, relatively isolated stars.  Hit "r" to check that
    the profiles are stellar.  Hit "a" to write the info to the screen,
    put it in a file called "hawaii.cen".  Try to get 5 stars.

3.  Run tstat.

	e.g. tstat hawaii.cen c3 --> mean sky = 0.0
	     tstat hawaii.cen c4 --> mean sky variance = 4.2
	     tstat hawaii.cen c5 --> mean fwhm = 5.0

4.  Update datapars.  

	fwhmpfs	= fwhm
	sigma	= sky variance
	datamin	= mean sky - 7*fwhm
	datamax = where detector goes nonlinear
	ccdread = from header?
	gain	= from header?

5.  Update centerpars.

	calgori	= centroid
	cbox	= 2*fwhm (sets center-finding size)

6.  Update fitskypars.
	
	annulus	= 4*fwhm (sets sky outer radius)
	dannulus= 3*fwhm (sets sky inner radius)

7.  Update photpars.

	aperturs= at least 1 fwhm (sets aperture size, use several!)

8.  Update daopars (psf photometry only).

	psfrad 	= 4*fwhm+1
	fitrad 	= fwhm

9.  Save these updates with setimpars.

	restore = no
	update  = yes
	
10. Fake a file with the positions of the objects of interest.  We
    want a few stars whose magnitude we know (i.e. central HDF) as
    well as ser_yprime.  (Or, run daofind at this point.)

	1610.20 1237.50	 (star1 hdf 4-454.0 m_i=20.8 V-I=-0.2 --> I=21.0)
	1308.03 1530.75  (star2 hdf 3-161.0 m_i=21.9 V-I=0.7  --> I=21.2)
	1562.47 1919.20  (star3 hdf 2-381.0 m_i=20.9 V-I=1.0  --> I=19.9)
	2610.02 2434.90  (ser_yprime)

11. Calculate the I band flux.

	star1 = 16720	--> seryprime I = 24.5
	star2 = 15240	--> seryprime I = 24.5
	star3 = 58000	--> seryprime I = 24.7
	seryprime = 697
	
FYI: The equation relating the I magnitude to the flux in the I band
image is:

	I = -2.5 log(f) + C

Look up I_1, the I band magnitude of a star in the central HDF.  
(This, of course, is STIS I, centered at 814.  LRIS is somewhere
around there.)  Measure the flux f_1 of this star.  Now measure the
flux of the object of interest, f_2.  Get the I band magnitude
of the object of interest with:

	I_1 - I_2 = -2.5 log(f_1/f_2).

%@%@%@%@%@%@%@%@%@%@%@%
Repeat in R band image!
%@%@%@%@%@%@%@%@%@%@%@%



05.30.00

Here's what I did to get I and R band magnitudes of ser_yprime.

1.  Get R band image (hdf_Rimage.fits).

2.  Pick out same stars; write "rband.cen". 

3.  Run tstat.

	e.g. tstat rband.cen c3 --> mean sky = 0.0
	     tstat rband.cen c4 --> mean sky variance = 0.14
	     tstat rband.cen c5 --> mean fwhm = 4.23

4.  Update datapars.  

	fwhmpfs	= fwhm
	sigma	= sky variance
	datamin	= mean sky - 7*fwhm
	datamax = where detector goes nonlinear
	ccdread = from header?
	gain	= from header?

5.  Update centerpars.

	calgori	= centroid
	cbox	= 2*fwhm (sets center-finding size)

6.  Update fitskypars.
	
	annulus	= 4*fwhm (sets sky outer radius)
	dannulus= 3*fwhm (sets sky inner radius)

7.  Update photpars.

	aperturs= at least 1 fwhm (sets aperture size, use several!)

8.  Update daopars (psf photometry only).

	psfrad 	= 4*fwhm+1
	fitrad 	= fwhm

9.  Save these updates with setimpars.

	restore = no
	update  = yes
	
10. Fake a file with the positions of the objects of interest.  We
    want a few stars whose magnitude we know (i.e. central HDF) as
    well as ser_yprime.  (Or, run daofind at this point.)

	598.61  284.93  (star1 hdf 4-454.0 m_i=20.8)
	328.13  544.06  (star2 hdf 3-161.0 m_i=21.9)
	551.56  892.46  (star3 hdf 2-381.0 m_i=20.9)
	1477.72 1363.45 (ser_yprime)

11. Calculate the R band flux with phot.

	star1 = 560 --> seryprime R = 25.4
	star2 = 258 --> seryprime R = 25.7
	star3 = 705 --> seryprime R = 25.8
	seryprime = 8